Streptococcus constellatus inhabits the healthy human gastrointestinal tract and oral microbiome; however, the incidence of this species becoming opportunistically pathogenic has increased in recent decades. S. constellatus has the potential to cause severe pyogenic infections requiring combination antibiotic therapy or surgical intervention. Some virulence processes in S. constellatus, such as genetic competence, are regulated through quorum sensing (QS), facilitated by its 16-mer competence stimulating peptide (CSP). Several target residues on the CSP molecule were identified that can be mutated to enhance the peptide activity and/or lead to competitive inhibition of the competence regulon QS circuitry, thereby modulating related pathogenic phenotypes. Using a rational design approach, second-generation peptide analog libraries were designed and screened, resulting in optimization of a competitive QS inhibitor, CSP-D1AI4AM6A, with an IC50 of 38.3 nM. Overall, this work provides a rational framework upon which novel QS modulators can be designed to attenuate virulence processes in this opportunistic pathogen.

Oral microbiome dysbiosis mediates the link between emotional disorders and systemic inflammation in heart failure.

Parvimonas micra is a specifically enriched bacterium in advanced canine periodontal disease and its effects are ameliorated using ADSCs-exosomes.

Scientific interest in the relationship between cardiovascular disease and the human microbiome has grown substantially in recent years, with particular emphasis placed on the gut microbiota. Emerging evidence suggests, however, that distinct microbial niches-including the skin, oral cavity, and gut-may interact to influence cardiovascular homeostasis through shared pathogenic pathways, most notably oxidative stress and systemic inflammation. Intestinal dysbiosis has been strongly linked to the increased production of microbial metabolites such as trimethylamine N-oxide, which promotes endothelial dysfunction, oxidative imbalance, and atherogenesis. The oral microbiome has similarly been implicated in cardiovascular pathology through mechanisms encompassing chronic low-grade inflammation, transient bacteremia, and direct vascular colonization by pathogenic species. The contribution of the skin microbiome to cardiovascular risk remains less well defined; nevertheless, chronic inflammatory dermatoses-psoriasis in particular-have been consistently associated with elevated cardiovascular risk, a relationship potentially mediated by systemic immune dysregulation and oxidative stress. This review synthesizes current evidence on the gut-oral-skin-cardiac microbiome axis, underscoring the central role of oxidative stress as a convergent pathogenic mechanism and examining potential therapeutic implications. A more comprehensive understanding of these interconnected systems may inform the development of novel, microbiome-targeted strategies for the prevention and management of cardiovascular disease.

The oral microbiome maintains the oral and systemic health. The extensive use of antimicrobial mouthwashes to control biofilm-related diseases has increased the concerns about their effect on microbial ecology. Specific formulations may cause microbial shifts which influences both the oral and systemic physiology in an individual. This systematic review evaluates the oral dysbiosis development after antimicrobial mouthwash use and correlates the microbial changes with clinical and systemic outcomes. A comprehensive search in various databases like PubMed, Scopus, etc. (till March 2025) was done. It identified 14 relevant studies from a total of 681 screened records. Risk of bias was assessed using ROB2, ROBINS-I, CRIS, and NOS tools, with data extracted on microbial diversity, taxonomic changes, nitrate reduction capacity, and antibiotic resistance. The findings showed that chlorhexidine caused the greatest dysbiosis and reduces the microbial diversity by 40-60%, with increasing Streptococcus spp. two-to-threefold, and elevating antibiotic resistance gene prevalence. Cetylpyridinium chloride and polyhexamethylene biguanide showed milder effects, thus preserving 70-80% of commensals, while herbal and plant-based rinses (o-cymen-5-ol, StellaLife®, Rosella) reduced pathogens by 25-40% without disrupting the balance. Fluoride-arginine formulations promote beneficial bacteria by 30-50% but marginally upregulated resistance genes, whereas mechanical hygiene methods maintained over 90% microbial diversity. Suppression of nitrate-reducing bacteria was associated with reduced nitric oxide bioavailability, potentially increasing vascular and cognitive risks. Hence, antimicrobial mouthwashes especially chlorhexidine induces significant dysbiotic shifts, while herbal, postbiotic, and mechanical alternatives demonstrate safer, microbiome thereby preserving the effects which is suitable for long-term oral health maintenance.

The factors influencing the oral microbiome during childhood and adolescence remain under-explored at the population level. Furthermore, details on how the oral microbiome differs with age, varies between individuals of different ethnicities, or is associated with socioeconomic factors and diet in children and adolescents are almost entirely unknown. Saliva samples and detailed demographic, health, diet and socioeconomic data were collected from children and adolescents that attended the Ontario Science Centre (Toronto, Canada) and were enrolled in the Spit for Science cohort. We characterised the bacterial microbiota of 4812 samples using 16S rRNA gene sequencing to make this the largest population cohort of the paediatric oral microbiome to date. Exploration of limited participant genotyping information and more than 50 variables encompassing the demographics, health, diet, socioeconomic status and living environment of participants revealed that almost all of the investigated variables were associated with overall community structure and/or the abundance of specific bacterial genera. However, most of these associations were modest (R2 < 0.01) and the correlation between genetic relatedness and salivary bacteriome similarity was weak (R2 = -0.014), while the strongest determinants of oral bacteriome composition were shared family/household environment (R2 = 0.61 in the subset of participants from multi-child households), age (R2 = 0.014) and ethnicity (R2 = 0.01). We show that older children and adolescents have higher richness but lower evenness than younger children, suggesting that their oral bacteriome changes as they are exposed to more influences outside the home, and that the oral bacteriome is more consistent with more core taxa among children and adolescents than adults. We also find that diet variables related to the frequency of sugar consumption have the largest impact on the oral bacteriome of children and adolescents, and that microbial differences attributed to ethnicity and diet are likely intertwined. This study provides an atlas of the demographic, health and lifestyle factors that are associated with the salivary bacteriome of children and adolescents. These findings highlight the complex interplay between social, environmental, and biological factors in shaping the developing oral microbiome and underscore the importance of inclusive, demographically diverse cohorts in microbiome research. This presents a reference for the variables that are important to account for in paediatric oral microbiome studies. Video Abstract.

This study investigated the role of interleukin-17 (IL-17) and the oral microbiome in peri-implant inflammation and bone loss under hyperglycemic and normoglycemic conditions. Wild-type (WT) and diabetic (db/db) mice with maxillary implants underwent ligature placement with or without IL-17A neutralization. Bone loss, osteoclast activity, inflammatory cytokines, Th17/Treg balance, and expression of IL-17Family members were analyzed. The oral microbiota was profiled by 16S rRNA sequencing, and its inflammatory potential was evaluated by co-culture with immune cells. Diabetic db/db mice exhibited greater peri-implant bone loss, osteoclast numbers, and RANKL/OPG ratios than WT, accompanied by elevated Il17a expression, reduced anti-inflammatory cytokines, enhanced Th17-associated inflammatory features, and altered FOXP3⁺ cell profiles. IL-17A neutralization significantly attenuated, but did not fully normalize, heightened inflammatory responses in db/db mice, whereas ligature-induced Il17f upregulation was observed only in db/db mice. Microbial alterations were partially shifted toward control profiles by IL-17A inhibition in WT mice, while diabetes-associated changes persisted regardless of ligation or anti-IL-17A. In vitro, peri-implant microbiota induced pro-inflammatory cytokine responses in splenocytes, with residual inflammatory responses remaining more evident in DB-derived microbiota after IL-17A inhibition. These findings suggest that peri-implantitis in diabetes is exacerbated by heightened IL-17-mediated inflammation and persistent microbial alterations, underscoring the need for more comprehensive therapeutic approaches to address the disease under diabetic conditions.

Over 90% of Asian American (AsA) adults are first- or second-generation immigrants, undergoing substantial environmental and sociocultural transitions; yet most environmental epidemiology cohorts have included few AsA participants. The Food and Microbiome Longitudinal Investigation (FAMiLI) is an environmental health cohort enriched with AsA adults (predominantly Korean and Chinese American) and designed to capture environmental exposures, dietary acculturation, and sociocultural factors across immigration generations. Its biobank-including buccal and stool specimens-supports research on the oral and gut microbiomes, human genomics, and other multi-omics. Since its launch in 2018, FAMiLI has completed baseline recruitment and biospecimen collection for 13,183 adults aged 40-75 years. The cohort is now expanding to include an additional 3,000 Asian American adults, bringing the total to approximately 16,000 participants, with an expected distribution of ~50% Asian American and ~50% from other racial/ethnic groups. This expansion provides an opportunity to examine AsA environmental health experiences within the broader U.S. FAMiLI is a unique national resource to address priority questions in environmental health, including microbiome and exposome science, individual susceptibility, and large-scale data analytics. The cohort supports investigation of critical windows of environmental change across the immigration experience, racial and ethnic disparities, and drivers of emerging health outcomes, including cancer, cardiovascular disease, diabetes and other outcomes. This cohort offers essential data to inform prevention strategies and shape public health policy to improve health outcomes in AsA communities.

Is Erosive Tooth Wear a Truly Non-Bacterial Condition? A Scoping Review.

Early childhood caries (ECC) is a prevalent dental disease with significant public health burdens. Oral microbiota plays a key role in caries development. Although several studies have compared the oral microbiota before and after caries treatment, few have investigated the dynamic changes in oral microbial communities beyond 3months. This 6-month prospective study monitored dynamic changes in the dental plaque microbiome, salivary pH, and oral hygiene status among children with ECC undergoing caries management. The outcomes were assessed at baseline (T0), immediately post-treatment (T1), and at 1-month, 3-month, and 6-month follow-ups (T2-T4). Children's oral hygiene status improved significantly after ECC management (p < 0.001). Their salivary pH levels increased at T1 but returned to the initial level during follow-up visits. Higher Chao1 scores were observed at T2, T3, and T4 when compared to T0 and T1 (p < 0.001). The principal coordinate analysis revealed distinct clustering patterns between baseline and post-treatment visits. Significant differences were observed in the relative abundance of Corynebacterium (p < 0.01), Corynebacterium matruchotii (p < 0.01), and Selenomonas noxia (p < 0.05) during the study period. The relative abundance of Corynebacterium and Corynebacterium matruchotii was significantly higher at T3 and T4 when compared to T1 (p < 0.01). Additionally, Saccharibacteria was positively correlated with children's dmfs scores and negatively correlated with children's salivary pH values. The above findings possibly indicated that comprehensive ECC management might be associated with dynamic changes in the oral microbiome. Further well-designed randomized controlled trials are warranted to determine the impact of dental treatment on oral microbiota dynamics. KEY POINTS: • Dynamic changes observed in the oral microbiome following dental treatment • Abundance of Saccharibacteria associated with children's caries status and salivary pH values • Children's oral health-related behaviors improved after comprehensive dental management.

Self-collected oral swab comparison for supragingival microbiome characterization.

Conventional periodontitis therapy is limited by the lack of an all-in-one material with the desired functions of toxin neutralization, pathogen eradication, and osteopromotion. Exploiting the innate capacity of macrophages to recognize and neutralize pathological stimuli, this study develops novel engineered macrophage-based materials: phytate/Zn2 +-loaded gelated macrophages (PZ-GMs). These materials are fabricated at room temperature by polymerizing polycationic hydrogels and loading phytate/Zn2 + into live macrophages, innovatively integrating the natural immune neutralization function of intact macrophage membranes with the bioactivity of intracellular hydrogels. PZ-GMs are found to eradicate >99.99% of pathogens, remove >90% of bacterial toxins, and eliminate >80% of related inflammatory factors, while simultaneously promoting bone repair through in situ mineralization and osteoinduction. They can be further incorporated into a hydrogel designed for acid-triggered release, ensuring targeted delivery to inflamed sites. In a murine periodontitis model, PZ-GMs facilitate periodontal regeneration via a dual mechanism: transforming the pathological microenvironment induced by bacteria and toxins and fostering the remodeling of an osteogenic microenvironment. Furthermore, oral microbiome homeostasis is restored. Collectively, PZ-GMs represent a promising all-in-one neutralization-eradication-osteopromotion material for highly efficient periodontitis therapy.

The oral microbiome is a diverse ecosystem that plays a critical role in health and disease and contains numerous bacterial species capable of metabolizing host-derived glycans, particularly sialic acids. Sialidase enzymes can be produced by both commensal and pathogenic bacteria influencing biofilm formation and host interactions. To investigate how sialidase activity might influence the oral microbiome, we conducted a series of in vitro polymicrobial biofilm experiments and assessed community composition using 16S rRNA sequencing. As a first step, we tested modified Oxford Nanopore Technology (ONT) primers using an in-house sequencing workflow and compared them to the standard Illumina MiSeq primers. Through in silico and in vitro assessments, we identified primer bias in the standard ONT 16S primers and designed human oral microbiome (HOM) modified primers (HOM_27F-YM/1492R-D) to improve taxonomic resolution, achieving results comparable to the gold-standard Illumina 16S primers particularly for key oral genera. These HOM-optimized primers had an overall lower error rate (3.4%) and generated community profiles that closely matched those produced by Illumina. We then used the same ONT workflow and modified 16S primers to evaluate the effects of the sialidase inhibitors oseltamivir and 2,3-dehydro-2-deoxy-N-acetylneuraminic acid on hydroxyapatite-coated minimum biofilm eradication concentration assay plate-derived plaque biofilms from a whole-plaque community model. Inhibitor-treated biofilms exhibited differences in relative abundance depending on the inhibitor combination used, with increased abundance of Streptococcus with oseltamivir alone and Fusobacterium with both inhibitors combined (Kruskal-Wallis cutoff=0.05, LDA>2). These findings demonstrate that ONT-based 16S sequencing with HOM-modified primers suggests that sialidase activity can modulate microbial community structure in plaque biofilms.

Background Osteoarthritis (OA) is a globally prevalent degenerative joint disorder that imposes significant socioeconomic burdens. While traditionally viewed as a localized “wear-and-tear” disease, emerging evidence supports a systemic pathogenesis involving the gut-joint axis. The oral-gut-joint pathway remains underexplored in OA pathophysiology. Objective This study aimed to characterize oral and gut microbiota signatures in OA patients and elucidate their functional connections to cartilage degeneration through multiomics integration. Methods We conducted a cross-sectional observational study involving 25 OA patients and 20 healthy controls. 16S rDNA gene amplicon sequencing was performed on fecal and oropharyngeal swab samples. Cartilage tissues were subjected to transcriptomic and proteomic analyses. Results We identified distinct dysbiosis patterns in both the gut and oral microbiomes of OA patients. The α-diversity of the gut microbiota significantly increased (P&amp;lt;0.05) with enrichment of Ruminococcaceae and Subdoligranulum . Concurrently, the oral microbiota showed increased α-diversity and activation of the lipopolysaccharide biosynthesis pathway. We constructed two significant cross-omics correlation modules: one linking gut microbes ( Lachnospiraceae and Muribaculaceae ) to cartilage inflammatory genes ( MAPK11 , ITGB3 , CD55 and ANGPT2 ) and extracellular matrix remodelling proteins and another connecting gut microbes ( Helicobacter , Pseudomonas , and Phocea ) with CXCL14 and GNGT2 . Conclusion Our study revealed the dysbiotic characteristics of the oral-gut microbiome and its complex associations with pathological changes in cartilage. These findings offer novel mechanistic insights and potential therapeutic targets for microbiota-based precision interventions in OA.

The demineralization of tooth enamel is the primary consequence of dental caries, leading to cavities and finally tooth loss. Erosive tooth wear from acidic beverages and food is another factor that degrades enamel. In both cases, an acidic environment leads to etching and the final dissolution of tooth mineral, i.e., hydroxyapatite. Here, this process is discussed from a chemical perspective, taking into account the solubility of calcium phosphate and the presence of the pellicle (protein layer) and plaque (bacterial biofilms), which both affect the dissolution rate. While low pH is definitely decisive, calcium-binding ligands (e.g., acid anions, proteins) contribute to dissolution by removing calcium ions from the equilibrium. This is an important effect in the oral cavity where the concentration of biomolecules is high. The situation is complicated by the fact that the composition of saliva and the oral microbiome vary considerably between individuals. The state of current knowledge on the demineralization of enamel is summarized and discussed, also in the context of approaches to prevent dental caries and erosive tooth wear.

Periodontal diseases, including both gingivitis and periodontitis, occur commonly among pregnant individuals. Both gingivitis and periodontitis are associated with adverse pregnancy outcomes (APOs) such as early pregnancy loss, preterm birth, preeclampsia, low birth weight, and stillbirth. This review highlights that the strongest mechanistic evidence linking periodontal diseases with APOs involves the domains of systemic inflammation, including increased pro-inflammatory cytokines and activation of matrix metalloproteases associated with preterm labor, and microbial translocation involving hematogenous dissemination of periodontopathic bacteria to the fetoplacental unit. Yet, other mechanistic domains remain underexplored, including maladaptive myelopoiesis with alterations of neutrophil activity, immune player trafficking with autoantibody development, masticatory dysfunction-diet interactions that may further increase risk of critical vitamin and nutritional deficiencies related to both periodontitis and APOs, and functional dysregulation of the oral microbiome including generation of nitric oxide that could impact pregnancy outcomes. Additionally, specific underlying vulnerabilities unique to pregnancy such as increased hormone production such as progesterone and cortisol likely impact the risk of periodontal diseases in pregnancy. By delving into these critical mechanistic domains, this review reveals both current understanding and critical areas for future research to overcome deficits in knowledge pertaining to how periodontal diseases in pregnancy lead to APOs. Elucidating these novel insights can promote scientific advancement, facilitate the development of novel interventions that prevent and/or treat periodontal diseases in pregnancy, and concurrently improve the lives and well-being of pregnant individuals and their children worldwide.

Changes to the oral microbiome have been reported in patients with Crohn's disease (CD). The aim of this study was to determine the characteristics and dynamics of the oral microbiome in children randomized to 1 of 2 nutritional treatments for CD. Participants (n = 54) in this randomized controlled trial (NCT02843100) received the Crohn's Disease Exclusion Diet (CDED) with either partial enteral nutrition (PEN; n = 28) or exclusive enteral nutrition (EEN; n = 26). The oral microbiome was assessed via swabs from the dorsum of the tongue and the buccal gingiva by 16S rRNA sequencing at 0, 2, 8, 14, 24, and 52 weeks. There were no significant differences in primary or clinical outcomes between the 2 groups. Due to the COVID-19 pandemic, sampling by 24 weeks was limited to 34 participants. At week 0, moderate-severe disease activity (Pediatric Crohn's Disease Activity Index [PCDAI] > 30) was associated with decreased Porphyromonas, Haemophilus, Alloprevotella, Neisseria, and Bergeyella species and increased Actinomyces. As patients entered remission (PCDAI < 10), we observed a restoration in the abundance of these taxa. A modified oral dysbiosis index (MODI) was generated, capable of distinguishing mild from moderate-severe disease activity based on microbiome profiles. Dysbiosis decreased as treatment continued and patients entered remission. Patients on CDED exhibited more significant dysbiosis index changes at weeks 8-24, compared with the EEN group. Application of the index across published oral microbiome data sets validated its ability to discriminate health from CD. Oral microbiome changes in pediatric CD reflect disease activity and parallel therapeutic response to CDED and EEN over time. Additional validation of the proposed dysbiosis index should be undertaken in adequately powered future studies.

IntroductionThe oral microbiome has been shown to be associated with respiratory health, primarily in adult case studies or among children. This relationship has been scarcely investigated in adult population-based cohorts.ObjectivesTo investigate the association between oral microbiome and respiratory health, more specifically asthma, chronic rhinosinusitis (CRS), lung function and fractional exhaled nitric oxide (FeNO) in a population-based cross-continental multicentre study among adults.MethodsSubgingival samples from 355 adult European Community Respiratory Health Survey participants from Norway, Australia and Estonia underwent metagenomic sequencing. Respiratory disease was defined from questionnaires and sensitisation from specific immunoglobulin E (IgE)/skin prick tests. Spirometry and FeNO were measured. The associations between alpha diversity and disease status were evaluated in cross-sectional analyses using logistic regression adjusting for sex, smoking and study centre. Differential abundance analyses were performed using analysis of compositions of microbiomes with bias correction.ResultsAlpha diversity differed by study centre and sensitisation status and was associated with non-allergic CRS (richness: 1.12, 95% CI 1.03 to 1.22). A similar though not statistically significant pattern was seen for forced vital capacity (FVC) below the lower limit of normal (LLN). Lachnospiraceae and Xanthomonas were more abundant in the oral microbiome of non-asthmatics and individuals without CRS, respectively, as compared with asthmatics and CRS patients. Several functional genes (1477–3391) and genera (54-98) were only present in the non-case groups, whereas individuals with affected respiratory health had 0–74 unique functional genes, but no unique genera present only in their respective groups.ConclusionIncreased alpha diversity was associated with non-allergic CRS and a similar trend was seen for FVC below LLN. Bacterial composition and functional profiles of the oral microbiome differed by respiratory health status. This study is novel in exploring functional gene profiling in relation to asthma and FeNO.

SUMMARYReptiles are a diverse and speciose class of animals that are broadly threatened by habitat loss, climate change, and other factors. From a microbiological perspective, reptiles have historically been examined as a source of disease, particularly salmonellosis, with most studies being culture-based investigations into causative agents of disease and potential for zoonoses. More recent work has sought to characterize the oral, skin, and gut microbiomes of reptiles more broadly to understand their contribution to reptile health and digestion. Non-avian reptiles are particularly interesting as ectothermic tetrapods, which usually lay eggs and have limited interaction with their young, as their digestion and life history strategies diverge substantially from the more well-studied mammals. Here, we review the reptile skin, oral, gut, eggshell, and nest microbiomes, along with the relationship between the microbiome and temperature stress. We present findings that distinguish the reptile microbiome from those of other studied vertebrate taxa, and place them in the context of their phylogenetic and ecological similarities to other animals. We discuss major disease-causing agents in reptiles, which was historically the main lens through which to view reptile microbiology, along with potential zoonoses. Finally, we examine how temperature and thermoregulation interact with the microbiome in reptiles, and how the microbiome may play a role in reptile conservation.

Bacterial adhesion and biofilm formation pose significant clinical challenges in clear aligner therapy, adversely affecting both oral health and aesthetics. In this study, a machine learning-driven strategy was used to develop a novel antimicrobial peptide (AMP), IW (sequence: IDFYRKTHWWNKLLAKWWAMR), which was subsequently covalently immobilized onto the surface of clear aligners to construct a pH-responsive antibacterial coating. In response to cariogenic acidic microenvironments, the coating is specifically activated to effectively inhibit the proliferation of cariogenic bacteria and subsequent biofilm formation. Moreover, IW reduces the abundance of potential pathogens while enriching health-associated bacterial genera, exerting a beneficial modulatory effect on the oral microbiome. This dual-functional strategy, integrating antibacterial activity with microbiota homeostasis preservation, offers a promising approach to combat cariogenic bacterial infection and oral dysbiosis, presenting substantial potential for clinical translation in orthodontic applications.